diff --git a/Dockerfile b/Dockerfile
index 25d3dce..874bd61 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -23,8 +23,8 @@ RUN apk --no-cache \
 
 # set environment variables
 ENV TZ=Etc/UTC
-ENV HOSTNAME=${HOSTNAME}
-ENV DOMAINNAME=${HOSTNAME#*.}
+ENV LOCAL_HOSTNAME=${HOSTNAME}
+ENV LOCAL_DOMAINNAME=${HOSTNAME#*.}
 ENV LOCAL_ENCRYPTION=false
 ENV SMARTHOST=""
 ENV SMARTHOST_PORT=587